[GFS2] Use a bio to read the superblock

This means that we don't need to create a special inode just to contain
a struct address_space in order to read a single disk block. Instead
we read the disk block directly. Its slightly faster, and uses slightly
less memory, but the real reason for doing this is that it removes a
special case from the glock code.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Steven Whitehouse 2006-07-27 13:53:53 -04:00
parent ae4a382004
commit f45b7ddd2b
4 changed files with 64 additions and 35 deletions

View File

@ -311,8 +311,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, uint64_t number,
/* If this glock protects actual on-disk data or metadata blocks,
create a VFS inode to manage the pages/buffers holding them. */
if (glops == &gfs2_inode_glops ||
glops == &gfs2_rgrp_glops ||
glops == &gfs2_meta_glops) {
glops == &gfs2_rgrp_glops) {
gl->gl_aspace = gfs2_aspace_get(sdp);
if (!gl->gl_aspace) {
error = -ENOMEM;

View File

@ -156,18 +156,6 @@ static void meta_go_inval(struct gfs2_glock *gl, int flags)
gl->gl_vn++;
}
/**
* meta_go_demote_ok - Check to see if it's ok to unlock a glock
* @gl: the glock
*
* Returns: 1 if we have no cached data; ok to demote meta glock
*/
static int meta_go_demote_ok(struct gfs2_glock *gl)
{
return !gl->gl_aspace->i_mapping->nrpages;
}
/**
* inode_go_xmote_th - promote/demote a glock
* @gl: the glock
@ -338,11 +326,12 @@ static void inode_go_unlock(struct gfs2_holder *gh)
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_inode *ip = gl->gl_object;
if (ip && test_bit(GLF_DIRTY, &gl->gl_flags))
gfs2_inode_attr_in(ip);
if (ip) {
if (test_bit(GLF_DIRTY, &gl->gl_flags))
gfs2_inode_attr_in(ip);
if (ip)
gfs2_meta_cache_flush(ip);
}
}
/**
@ -507,9 +496,6 @@ static int quota_go_demote_ok(struct gfs2_glock *gl)
struct gfs2_glock_operations gfs2_meta_glops = {
.go_xmote_th = gfs2_glock_xmote_th,
.go_drop_th = gfs2_glock_drop_th,
.go_sync = meta_go_sync,
.go_inval = meta_go_inval,
.go_demote_ok = meta_go_demote_ok,
.go_type = LM_TYPE_META
};

View File

@ -310,11 +310,6 @@ static int init_sb(struct gfs2_sbd *sdp, int silent, int undo)
sdp->sd_sb.sb_bsize, (unsigned int)PAGE_SIZE);
goto out;
}
/* Get rid of buffers from the original block size */
sb_gh.gh_gl->gl_ops->go_inval(sb_gh.gh_gl, DIO_METADATA | DIO_DATA);
sb_gh.gh_gl->gl_aspace->i_blkbits = sdp->sd_sb.sb_bsize_shift;
sb_set_blocksize(sb, sdp->sd_sb.sb_bsize);
/* Get the root inode */

View File

@ -14,6 +14,7 @@
#include <linux/buffer_head.h>
#include <linux/crc32.h>
#include <linux/gfs2_ondisk.h>
#include <linux/bio.h>
#include "gfs2.h"
#include "lm_interface.h"
@ -157,6 +158,54 @@ int gfs2_check_sb(struct gfs2_sbd *sdp, struct gfs2_sb *sb, int silent)
return 0;
}
static int end_bio_io_page(struct bio *bio, unsigned int bytes_done, int error)
{
struct page *page = bio->bi_private;
if (bio->bi_size)
return 1;
if (!error)
SetPageUptodate(page);
unlock_page(page);
return 0;
}
static struct page *gfs2_read_super(struct super_block *sb, sector_t sector)
{
struct page *page;
struct bio *bio;
page = alloc_page(GFP_KERNEL);
if (unlikely(!page))
return NULL;
ClearPageUptodate(page);
ClearPageDirty(page);
lock_page(page);
bio = bio_alloc(GFP_KERNEL, 1);
if (unlikely(!bio)) {
__free_page(page);
return NULL;
}
bio->bi_sector = sector;
bio->bi_bdev = sb->s_bdev;
bio_add_page(bio, page, PAGE_SIZE, 0);
bio->bi_end_io = end_bio_io_page;
bio->bi_private = page;
submit_bio(READ | BIO_RW_SYNC, bio);
wait_on_page_locked(page);
bio_put(bio);
if (!PageUptodate(page)) {
__free_page(page);
return NULL;
}
return page;
}
/**
* gfs2_read_sb - Read super block
* @sdp: The GFS2 superblock
@ -167,23 +216,23 @@ int gfs2_check_sb(struct gfs2_sbd *sdp, struct gfs2_sb *sb, int silent)
int gfs2_read_sb(struct gfs2_sbd *sdp, struct gfs2_glock *gl, int silent)
{
struct buffer_head *bh;
uint32_t hash_blocks, ind_blocks, leaf_blocks;
uint32_t tmp_blocks;
unsigned int x;
int error;
struct page *page;
char *sb;
error = gfs2_meta_read(gl, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift,
DIO_FORCE | DIO_START | DIO_WAIT, &bh);
if (error) {
page = gfs2_read_super(sdp->sd_vfs, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift);
if (!page) {
if (!silent)
fs_err(sdp, "can't read superblock\n");
return error;
return -EIO;
}
gfs2_assert(sdp, sizeof(struct gfs2_sb) <= bh->b_size);
gfs2_sb_in(&sdp->sd_sb, bh->b_data);
brelse(bh);
sb = kmap(page);
gfs2_sb_in(&sdp->sd_sb, sb);
kunmap(page);
__free_page(page);
error = gfs2_check_sb(sdp, &sdp->sd_sb, silent);
if (error)
@ -202,7 +251,7 @@ int gfs2_read_sb(struct gfs2_sbd *sdp, struct gfs2_glock *gl, int silent)
sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(uint64_t);
sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
sizeof(struct gfs2_meta_header)) /
sizeof(struct gfs2_quota_change);
sizeof(struct gfs2_quota_change);
/* Compute maximum reservation required to add a entry to a directory */